TWI421583B - Variable angle of the liquid crystal display - Google Patents

Description

Variable viewing angle liquid crystal display

The present invention relates to a display, and more particularly to a liquid crystal display having a variable viewing angle that can play video.

"Liquid crystal display (LCD)" has the characteristics of lightness, thinness, bright color, etc., and has gradually replaced traditional CRT monitors, becoming an indispensable electronic product in every family life. Since the liquid crystal display must rely on the backlight module to provide the required backlight, the backlight module has replaced the cold cathode tube (CCFL) as a light source by using a power-saving, small-sized, long-life light-emitting diode (ED). However, the backlight module is still the main cause of energy consumption.

Referring to FIG. 1 , a backlight module 1 of a general direct type is taken as an example, and mainly includes a diffusion sheet 11 for diffusing light, and a plurality of light sources 12 (light emitting diodes or cold cathode tubes) disposed behind the diffusion sheet 11 . And a plurality of cymbals 13 disposed in front of the diffusion sheet 11 for correcting light. Since the direct type backlight module 1 does not require the microstructure of the light guide plate to destroy the total light reflection phenomenon, it has the advantages of simple structure, high luminance, good light-emitting viewing angle, high light utilization efficiency, etc., but the diffusion sheet 11 In the process of refracting, reflecting and scattering light, although the optical diffusion effect can be achieved, the light is blurred and the directivity of the light is poor. Therefore, the ridges 13 must be used to correct the horizontal and vertical directions of the light.

However, multinational company 3M is the exclusive global supplier of 稜鏡片13, and has a number of related patents, and these slabs 13 account for about 3-4% of the total cost of the backlight module 1, resulting in the backlight module 1 cost cannot be effectively reduced. .

In addition, members of the family watching the display are sometimes viewed by a group of people, but sometimes they are only watched by themselves, while the traditional variable-view liquid crystal display is usually designed for multi-person viewing, so the backlight has a wide viewing angle. When watching the display alone, in fact, only a narrow backlight perspective is needed to meet the viewing requirements. At this time, the light energy of other viewing angles will be wasted, resulting in unnecessary power consumption.

Accordingly, it is an object of the present invention to provide a liquid crystal display having a variable viewing angle that can achieve energy saving and power saving requirements.

Another object of the present invention is to provide a backlight module for a liquid crystal display having a variable viewing angle that can save material costs.

Therefore, the variable viewing angle liquid crystal display of the present invention comprises a liquid crystal display module, a backlight module, and a microlens array module. The backlight module is located behind the liquid crystal display module and is used to supply the light source required by the liquid crystal display module. The microlens array module cooperates with the backlight module to generate a surface light source, and has a plurality of microlenses that can change the curvature, so that the surface light source changes the light viewing angle according to the curvature.

The backlight module of the present invention is applied to a variable viewing angle liquid crystal display, comprising a diffusion sheet, at least one light emitting element, and a lens unit. The diffuser is for a diffused light source. The light-emitting element is disposed behind the diffusion sheet and diverges the light source relative to the diffusion sheet. The lens unit is disposed between the diffusion sheet and the light-emitting element, and is configured to guide light into a diffusion source to generate a parallel light source.

The efficacy of the present invention is in the case of satisfying one or more people's viewing needs Appropriately change the light viewing angle and adjust the energy consumed by the light to achieve energy saving.

Another effect of the present invention is to replace the function of the general cymbal with the lens unit, thereby achieving the purpose of reducing the material cost.

The above and other technical contents, features and advantages of the present invention will be apparent from the following detailed description of the preferred embodiments.

Referring to FIG. 2, a preferred embodiment of the variable viewing angle liquid crystal display of the present invention comprises a liquid crystal display module 2, a backlight module 3 (FIG. 5), and a microlens array module 4.

The liquid crystal display module 2 has a first substrate 21, a color filter 22, a first transparent conductive film 23, a liquid crystal layer 24, a second transparent conductive film 25, and a second substrate 26 stacked on each other. And a first polarizer 27. Each of the sub-pixels of the color filter 22 has three color points 221, 222, and 223 of red, green, and blue.

Referring to FIG. 5 , the backlight module 3 is located behind the liquid crystal display module 2 and has a diffusion sheet 31 for diffusing light, and a plurality of illuminations disposed behind the diffusion sheet 31 and diverging the light source relative to the diffusion sheet. The element 32 and a lens unit 33 disposed between the diffusion sheet 31 and the light-emitting elements 32. The light-emitting elements 32 are respectively a light-emitting diode in the preferred embodiment. The lens unit 33 has a number of first lenses 331 corresponding to the light-emitting elements 32 and for guiding light into the parallel light source into the diffusion sheet 31, and the number corresponds to the first lens 331 and is used to guide the light source into The first lens The second lens 332 of the number 331. The first lens 331 is a plano-convex lens having a radius of curvature R = 3 mm in the preferred embodiment. In the preferred embodiment, the second lens 332 is a plano-convex lens having a radius of curvature of R=17 mm, and can be integrally packaged with the light-emitting diode (light-emitting element) as a lampshade of the light-emitting diode.

Referring to FIG. 2 and FIG. 3 and FIG. 4 , the microlens array module 4 is stacked on the first substrate 21 of the liquid crystal display module 2 and has a third transparent conductive film 41 and a layer stacked on each other. The hydrophilic layer 42 is formed in a microarray manner corresponding to each of the color points 221, 222, 223 to form a microlens unit 43 on the hydrophilic layer 42 and which can change the curvature, and a second polarizer 44. The microlens unit 43 achieves the purpose of changing the radius of curvature by using a variable curvature microlens array technology. The driving methods of the aforementioned variable focal lens array technology can be divided into two categories: changing the curvature of the film or interface to achieve zooming, or Change the characteristics of the material itself to achieve the purpose of zooming. In the preferred embodiment, reference is made to the prior art (S. Kuiper and BHW Hendriks, "Variable-focus liquid lens for miniature cameras," Appl. Phys. Lett., vol. 85, no. 7, pp. 1128- 1130, 08 2004.) Simulating the first mode of changing the radius of curvature of the microlens unit 43 having the photoresist layer 431 coated on the second polarizer 44 is soft baked and etched. The developing process and the like form a plurality of grooves 432, and then hard baked, coated with a fourth transparent conductive film 433, a hydrophobic layer 434, and added with water droplets, and packaged integrally with the liquid crystal display module 2. The hydrophobic layer 434 has a hydrophobic property that allows the water droplets to aggregate and form a plurality of microlenses 435. When the third and fourth transparent conductive films 41, 433 are electrically conductive, water molecules in the microlenses 435 are produced. The polarization reaction is generated, thereby increasing the radius of curvature of the microlenses 435, and the purpose of changing the radius of curvature is achieved as the voltage magnitude is different. Since the size of the microlens array is about several tens of micrometers, the effects of surface adhesion and surface tension are much greater than gravity (about 1000:1), so the influence of gravity can be ignored.

Referring to Appendix 1, the following description of the present invention in conjunction with the foregoing preferred embodiments is as follows: Photometric formula:

L: luminance, I ₀ : light intensity, A: illuminated surface area, Φ: luminous flux, dω : solid angle, ds _o : luminous area, cos θ: angle between the observer's observation direction and the normal direction of the light-emitting area.

According to the above photometric formula, when the luminous flux Φ becomes large, the light intensity I ₀ and the luminance L are also increased, and in practice, the radius of curvature of the microlenses 435 is small, and the direction of the light source is more concentrated, so that The luminous flux Φ of the unit solid angle dω rises in the front, and is referred to in Annex 1. Therefore, when the luminous flux Φ remains unchanged, the light intensity I ₀ and the luminance increase as the unit solid angle in front increases, and at this time, the micro The radius of curvature of the lens 435 tends to be smaller and smaller. However, when the luminance L reaches 620 nit, it has exceeded the demand of a liquid crystal display having a variable viewing angle (about 400 to 600 nit) on the general market. If the luminance L is maintained at 500 nit and the light intensity I ₀ is 1.25 cd, it can be found that when the radius of curvature of the microlenses 41 is reduced from 5 mm to 0.5 mm, the luminous flux Φ can be reduced from 221 m to 6.541 m, and reduced. The backlight viewing angle is reduced from 100° to 42°, and as the luminous flux Φ decreases, the power consumption also decreases, and the energy saving effect can be achieved.

Referring to FIG. 5, FIG. 6, and FIG. 3, when the light-emitting elements 31 diverge the light source, the second lens 332 can collect the light source and introduce the first lens 331 to make the first lens 331 The light is directed to generate a parallel light source into the diffusion sheet 31, diffused into a uniform surface light source, and then transmitted through the zoom lenslet lens technology to drive the microlenses 435 to change the radius of curvature, so that the backlight viewing angle is expanded to be suitable. The 100° watched by the person enhances the degree of clarity and comfort during viewing, or is reduced to 42° suitable for one person to watch, thereby meeting the viewing demand and achieving energy saving.

As can be seen from the accessory 2, the present invention can effectively reduce the energy consumption by up to 70%, and it is worth mentioning that the variable viewing angle liquid crystal display of the present invention can be combined with a "+" of a remote controller (not shown). -" button (not shown), directly increase or decrease the viewing angle of the liquid crystal display with the variable viewing angle, or carry a detecting device (not shown) to confirm the number of viewers, and can control the change of the liquid crystal display with the variable viewing angle The microlenses 41 have a radius of curvature to adjust the viewing angle of the light.

According to the above description, the variable viewing angle liquid crystal display of the present invention has the following advantages and effects:

1. Since the present invention combines the diffusion sheet 31 with the lens unit 33 to achieve the purpose of correcting the light direction, the present invention can effectively reduce the cost, in addition to the need to provide the cymbal.

2. The present invention can adjust the required energy (light flux) by changing the radius of curvature of the microlenses 41 so that the viewing angle is changed from a wide-angle angle viewed by a plurality of people to a narrow-field angle suitable for single-person viewing. The energy consumption is as high as 70%, which makes the invention meet the environmental protection requirements of energy saving and power saving.

The above is only the preferred embodiment of the present invention, and the scope of the invention is not limited thereto, that is, the simple equivalent changes and modifications made by the scope of the invention and the description of the invention are All remain within the scope of the invention patent.

2‧‧‧LCD module

21‧‧‧First substrate

22‧‧‧Color filters

221‧‧‧ color point

222‧‧‧ color point

223‧‧‧ color point

23‧‧‧First transparent conductive film

24‧‧‧Liquid layer

25‧‧‧Second transparent conductive film

26‧‧‧second substrate

27‧‧‧First polarizer

3‧‧‧Backlight module

31‧‧‧Diffuse film

32‧‧‧Lighting elements

33‧‧‧ lens unit

331‧‧‧ first lens

332‧‧‧second lens

4‧‧‧Microlens array module

41‧‧‧ Third transparent conductive film

42‧‧‧Hydrophilic layer

43‧‧‧Microlens unit

431‧‧‧Photoresist layer

432‧‧‧ Groove

433‧‧‧fourth transparent conductive film

434‧‧‧hydrophobic layer

435‧‧‧Microlens

44‧‧‧Second polarizer

1 is a schematic view showing a backlight module of a general direct type; FIG. 2 is a schematic view showing a preferred embodiment of a variable viewing angle liquid crystal display of the present invention; and FIG. 3 is a microlens unit of the preferred embodiment. FIG. 4 is a cross-sectional view showing the radius of curvature of the microlens unit being reduced in the preferred embodiment; FIG. 5 is a cross-sectional view showing the enlarged viewing angle of the preferred embodiment; Figure 6 is a cross-sectional view showing the reduced viewing angle of the preferred embodiment.

[A brief description of the attachment]

Annex 1: Comparison of results of different luminances under the same luminous flux value; Annex 2: Comparison of results of different luminous fluxes under the same luminance value; and Annex 3: Schematic diagram of light source constructed by optical simulation software.

2‧‧‧LCD module

21‧‧‧First substrate

22‧‧‧Color filters

221‧‧‧ color point

222‧‧‧ color point

223‧‧‧ color point

23‧‧‧First transparent conductive film

24‧‧‧Liquid layer

25‧‧‧Second transparent conductive film

26‧‧‧second substrate

27‧‧‧First polarizer

3‧‧‧Backlight module

31‧‧‧Diffuse film

32‧‧‧Lighting elements

33‧‧‧ lens unit

331‧‧‧ first lens

332‧‧‧second lens

4‧‧‧Microlens array module

435‧‧‧Microlens

44‧‧‧Second polarizer

Claims (5)

A variable-view liquid crystal display comprising: a liquid crystal display module; a backlight module having a diffusion sheet for diffusing light, a light source disposed behind the liquid crystal display module and supplying the liquid crystal display module At least one light-emitting element, and at least one first lens, the first lens is used for guiding light to generate a parallel light source into the diffusion sheet; and a microlens array module is used to generate a surface light source with the backlight module. And having a plurality of microlenses that change the curvature by the zoom microlens array technology, so that the surface light source changes the light viewing angle according to the aforementioned curvature. The variable-view liquid crystal display according to claim 1, wherein the light-emitting element may be one of a light-emitting diode and a cathode ray tube. The liquid crystal display of the variable viewing angle of claim 1, wherein the backlight module further has at least one second lens, wherein the second lens is a light source for guiding the light emitting element into the first lens. . The variable-view liquid crystal display of claim 1, wherein the microlens array module is located in front of the liquid crystal display module. The variable viewing angle liquid crystal display of claim 1, wherein the microlenses are arranged in an array.